Numerous devices need a source of a reliable, precise frequency to carry out their functions. The functions of a device often involve synchronous operation with other devices, synchronization of functions within the device itself, precise timekeeping, and numerous other operations involving the use of a precise frequency. Today, quartz oscillators are in wide use for precise frequency generation. Such oscillators come in many configurations, from simple crystal oscillators to double oven quartz oscillator designs. Such designs cover a wide range of frequencies and stabilities. In configurations designed for high performance, the oscillator performance is determined by the physics of the quartz resonator, the supporting circuit around the quartz resonator, and environmental factors. At the system level, factors affecting overall oscillator and synchronization stability include temperature changes, supply voltage changes, aging rates, steering linearity and gain variations, analog control voltage drift, and numerous other factors. Developments of new devices and needs to provide efficient service in many applications are driving demands for better and better synchronization performance. Equipment manufacturers naturally wish to provide synchronization performance without resorting to excessively expensive techniques for frequency generation.